Proteomic analysis of cervical cancer cells treated with adenovirus-mediated MDA-7
CANCER BIOLOGY & THERAPY
Authors: Wei, Lili; Wang, Zhongtang; Cui, Tao; Yi, Faping; Bu, Youquan; Ding, Songtao; Ma, Yongping; Song, Fangzhou
Abstract
Ad.mda-7 inhibited growth and decreased survival in a broad array of human tumor cells, without eliciting detrimental effects in normal cells. This study demonstrates that Ad.mda-7 can effectively impede the proliferation and induce apoptosis of human cervical carcinoma cells, but the underlying mechanisms inducing cell death at protein level are unknown. Using proteome analysis, an investigation aimed at a better understanding of the antiproliferative mechanisms by Ad.mda-7 was carried out in CaSki cervical cancer cells. A total of 43 differentially expressed proteins were visualized by 2-DE and silver stain., 29 proteins of which were identified via matrix-assisted laser desorption/ionization-time of flight mass spectrometry(MALDI-TOF-MS) analysis, 15 were upregulated (e. g., Tumor suppressor p53, Apoptosis regulator BAX, Adenylate kinase isoenzyme 1(AK1), Growth arrest and DNA-damage-inducible protein GADD45 gamma (GADD45.)) and 14 were downregulated (e. g., Eukaryotic translation initiation factor 5A(eIF-5A), Protein DJ-1, Annexin V, Transcription elongation factor B polypeptide 2 (TCEB2), TRAF family member-associated NFkB activator (TRAF2), c-Myc-responsive protein Rcl (RCL)). Among the identified proteins, the protein and mRNA alterations of six proteins were further confirmed by Western blot and semi-quantitative RT-PCR. Together, at both the mRNA and protein levels, p53, BAX, AK1, GADD45. and BCCIP were upregulated, while eIF-5A was downregulated following Ad.mda-7 treatment. Our findings may offer new insights into the antiproliferative mechanisms by Ad. mda-7 and its mode of action in cervical carcinoma cells.
The C-terminal cytoplasmic tail of hedgehog receptor Patched1 is a platform for E3 ubiquitin ligase complexes
MOLECULAR AND CELLULAR BIOCHEMISTRY
Authors: Yamaki, Yuka; Kagawa, Hiroki; Hatta, Tomohisa; Natsume, Tohru; Kawahara, Hiroyuki
Abstract
The Sonic hedgehog (Shh) signaling pathway plays a crucial role in cell proliferation and differentiation via Patched1 (Ptc1), a 12-pass transmembrane receptor protein. The C-terminal cytoplasmic tail of Ptc1 can be cleaved to release the 7th intracellular domain (ICD7), whose function is still unclear. In this study, we found that the ICD7 fragment of Ptc1 associates with polyubiquitinated species. Using mass spectrometry, we identified a cluster of E3 ubiquitin ligase complex as novel Ptc1 ICD7-binding proteins. In particular, Ptc1 ICD7 interacted with most components of the Cullin-2 (CUL2)-based E3 ligase complex, including TCEB1 (EloC), TCEB2 (EloB), ZYG11B, and CUL2 itself. To address the significance of CUL2-based E3 ligase in Ptc1 function, we examined the effects of CUL2 knockdown on Shh-induced osteoblast differentiation in the mesenchymal stem cell line C3H10T1/2. Indeed, knockdown of CUL2 abolished the Shh-induced stem cell differentiation. These results suggest that CUL2-based E3 ligase complex may play a role in Shh- and Ptc1-dependent signaling pathways.